...
【24h】

On turbulence in dilatant dispersions

机译:关于膨胀分散中的湍流

获取原文
获取原文并翻译 | 示例
           

摘要

This paper presents a new theory on the behaviour of shear-thickening (dilatant) fluids under turbulent conditions. The structure of a dilatant colloidal fluid in turbulent motion may be characterized by (at least) four characteristic length scales: (i) the 'statistically largest' turbulent scale, lambda(0), labeling the begin of the inertial part of the wavenumber spectrum; (ii) the energy-containing scale, L; (iii) Kolmogorov's micro-scale, lambda(K), related with the size of the smallest vortices existing for a given kinematic viscosity and forcing; (iv) the inner ('colloidal') micro-scale, lambda(i), typically representing a major stable material property of the colloidal fluid. In particular, for small ratios r = lambda(i)/lambda(K) similar to O (1), various interactions between colloidal structures and smallest turbulent eddies can be expected. In the present paper we discuss particularly that for rho = lambda(0)/lambda(K) -> O (1) turbulence (in the narrow, inertial sense) is strangled and chaotic but less mixing fluid motions remain. We start from a new stochastic, micro-mechanical turbulence theory without empirical parameters valid for inviscid fluids as seen in publications by Baumert in 2013 and 2015. It predicts e.g. von Karman's constant correctly as 1/root 2 pi = 0.399. In its generalized version for non-zero viscosity and shear-thickening behavior presented in this contribution, it predicts two solution branches for the steady state: The first characterizes a family of states with swift (inertial) turbulent mixing and small lambda(K), potentially approaching lambda(i). The second branch characterizes a state family with rho -> O (1) and thus strangled turbulence, rho approximate to O(1). Stability properties and a potential dynamic commuting between the two solution branches had to be left for future research.
机译:本文提出了在湍流条件下剪切增稠(膨胀)流体行为的新理论。湍流中膨胀胶体流体的结构可以通过(至少)四个特征长度尺度来表征:(i)“统计上最大”的湍流尺度lambda(0),标记波数频谱的惯性部分的开始; (ii)含能尺度L; (iii)柯尔莫哥洛夫的微米级(λ),与给定的运动粘度和强迫作用下存在的最小涡旋的大小有关; (iv)内部(“胶体”)微米级lambda(i),通常代表胶体流体的主要稳定材料特性。特别是,对于类似于O(1)的小比例r = lambda(i)/ lambda(K),可以预期胶体结构与最小湍流之间的各种相互作用。在本文中,我们特别讨论的是,对于rho = lambda(0)/ lambda(K)-> O(1),湍流(在狭窄的惯性意义上)被勒死并且混乱,但混合流体的运动较少。我们从Baumert在2013年和2015年的出版物中看到的,没有经验参数对无粘性流体有效的新的随机,微机械湍流理论开始。 von Karman的常数正确为1 / root 2 pi = 0.399。在此贡献中提出的非零粘度和剪切增稠行为的广义版本中,它预测了稳态的两个解分支:第一个描述具有快速(惯性)湍流混合和小λ(K)的状态族,可能接近lambda(i)。第二个分支用rho-> O(1)表征一个状态族,因此扼杀了湍流,rho近似于O(1)。两个解决方案分支之间的稳定性和潜在的动态换向必须留待将来研究。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号